Credential stuffing has become an increasingly more popular mechanism of attack against organizations that employ online user authentication. The rise in such activity is the direct result of to the volume of compromised credentials that are being made available to attackers. The tools that may be used for these attacks are being created and modified by developers, and shared on underground forums. Credential stuffing tools can exist as applications or scripts on the attacker's machines. Alternatively, these tools can be hosted on websites, thereby making the tools widely available to additional attackers via simple search queries. The use of these easily accessible tools can produce security compromises that result in monetary loss to consumers and/or merchants.